Antenna



FIG. 1 is a front elevation view of an antenna according to the present invention;

FIG. 2 is a rear elevation view thereof; and,

FIG. 3 is front elevation view of the antenna within an environment.

All elements of the claimed design are flat and coplanar. The broken lines in FIG. 3 illustrate environment and form no part of the claimed design. 

CLAIM The ornamental design for an antenna, as substantially shown and described. 